


Infidelity

by GhostGarrison



Category: Supernatural
Genre: Cheating, Established Relationship, Infidelity, M/M, Past Dean Winchester/Sam Winchester, Threesome
Language: English
Status: Completed
Published: 2015-01-20
Updated: 2015-01-20
Packaged: 2018-03-08 10:05:49
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,165
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3205262
Author URL: https://archiveofourown.org/users/GhostGarrison/pseuds/GhostGarrison
Summary: <blockquote class="userstuff">
              <p>Castiel has done something very, very bad. His boyfriend Dean is wonderful and perfect in every way... but so is his little brother Sam.</p>
            </blockquote>





	Infidelity

Castiel has done something very, _very_ bad.

How could he be this stupid? Dean has been such a good boyfriend to Castiel—one that makes him mixtapes on their anniversaries and sometimes ‘just because’ and makes him breakfast in bed when he has exams and knows where he likes to be touched and always puts him first and foremost during sex—and he basically just stomped on it with iron-toed boots. The exact kind that Dean wears.

What is he, an idiot? The biggest asshole to ever roam the planet? He must be, due to this.

But _god_ , Sam was just so _good_. He’s taller—much taller than Dean, with a bit more muscle and strength—with amazing hazel eyes that glint in the sunlight, and long shaggy hair that felt amazing to run his hands through and to grip onto when Sam thrusted into him. His voice is smooth like velvet, soothing but with the perfect touch of dominating when he wants to be, which turned Castiel on past the point of no return. Sam liked it rough, and that was something that Dean almost never gave to Castiel in fear of ‘hurting him.’ Sam was able to lift him up, pin him against the wall and talk dirty while giving it to him _hard_. He even stayed until the morning, before disappearing through the door to probably return to Dean’s off-campus apartment where he is staying for the weekend to visit his brother.

The night started out as a drunken frenzy, but Castiel was still aware that he was getting into bed with his boyfriend’s _brother_. And now, here he lies under the sheets of his apartment bed, feeling the weight of what he has done crush him and feeling the dried come on his stomach that he should really go and wash off.

He dons bruises and bitemarks from another man, and when he sees them in the mirror, he somehow feels like he can’t regret it at all.

What will he possibly tell Dean? _"Sorry, I got drunk last night and decided your brother was number one on my list to fuck so I did"_? No, definitely not. Dean would be so angry.

Maybe he shouldn’t tell Dean at all. But that would be lying, and Castiel isn’t any good at keeping secrets.

Castiel shows up at Dean’s apartment, clean and shaven and feeling guiltier than he’s ever felt before. But he _does_ show up, he uses the key that Dean gave him earlier in the year, when they celebrated their second anniversary of going out—

He has to stop that thought right in its tracks or else he’ll make himself sick.

Halfway through the door into the small dark hallway of the apartment, Castiel wonders if he’s still able to turn around and leave, but then a voice calls out. Dean.

"Cas? That you?"

"Yes," Castiel says, silently sighing before stepping fully into the apartment. He kicks his shoes off and tries to gear himself up to face his fate.

Would Dean break up with him? Would they continue to date and treat this as a rough patch, water under a bridge? Move on like it never happened? Will Dean kick him out on his ass and tell him to never talk to him again?

Castiel’s steps are unsteady as he walks towards the kitchen, the light from the room spilling out into the hall.

His heart drops when he sees it.

Sam is sitting at Dean’s small kitchen table, face in his hands and a knowing smirk on his face. Dean sits across from him, beer in hand, looking up to Cas in the doorway once before beckoning him in. “I wanna talk to you.”

Oh god, this is it, isn’t it? Castiel’s mouth goes dry, fighting down the urge to run. Dean’s going to break up with him right there, in front of his brother…. his brother _Sam_ who must have told him!

Cas ignores how much he wants to either walk out of the room or walk over to Sam and slap him across the face. Neither, he tells himself, do neither.

"So, Sammy here," Dean starts, smiling and slapping a hand on Sam’s clothed thigh and letting it linger there, rubbing in small circles, "tells me that you two had a good time last night."

"Oh?" Castiel says, innocently. They were supposed to just go out to a bar while Dean finished up an evening class, just to get to know each other. And then _that_ happened. Ugh.

"A _real_ good time,” Dean says, voice dropping lower as he raises an eyebrow.

Castiel just blinks. It’s obvious that Dean knows, right? He knows about last night, he knows about Sam and himself… but why doesn’t he look angry?

"Hey, man," Dean continues, raising a hand in surrender, "I know what you’re thinking, and no, I’m not mad about it."

Castiel blinks again. What?

"Sam and I have been talkin’ and well, let’s just say we’ve come to a little mutual understanding," Dean says with a wink, and Sam nods beside him. "Tell me, Cas, did you like fucking Sam?"

He still doesn’t understand, so he says nothing but stares wide-eyed at the two brothers.

"Did you like fucking with my brother? … It’s a simple question, Cas, come on," Dean says with a smile, like he’s joking and Castiel can’t even fathom what is actually happening right now. "Sam’s got long legs, and he’s really strong. And I know for a fact that he’s pretty well-endowed, don’t you think? I bet he gave you a killer blowjob—I like them, so I bet you did too."

That’s when Castiel chooses to speak. “Wh-what?” he sputters. Dean is… Dean is talking about having sex with Sam himself? Knowing explicitly how Sam is in bed? How he likes to fuck and what amazing blowjobs he gives?

 _… What_?

"Sam and I have been talkin’," Dean says, repeating himself once more, "And I was wondering if you’d be interested in a Winchester-combo, a two-for-one special."

He stares at them more, unable to form any words in his head.

"Sam couldn’t shut up about how ‘good your boyfriend was in bed’," Dean says, poorly mimicking his brother’s voice, who just laughs at his brother from a foot away. "So maybe instead of just the two of us, it could be the three of us next time?"

Castiel is speechless, completely and utterly speechless. He came here to get dumped, he came here to get yelled at, cried at, maybe punched or slapped by an angry Dean but not… get asked to an incestuous threeway.

Yet here he is, mentally frozen and being pulled by the wrist toward’s Dean’s bedroom—a room he knows well—being trailed by Sam Winchester, who is already shedding his shirt and throwing it to the floor.

Over the next two hours, Castiel stops feeling like he’s cheated and more like he’s just gained another boyfriend and lover.


End file.
